Aerostat.



J. R. GAMMETER.

AEROSTAT.

APPLICATION FILED MAR. 12

Patented Nov. 24, 1914.

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Patented Nov. 24, 1914.

2 SHEETS-SHEET 2.

JOHN B. GAMMETER, 0F AKRON, OHIO.

AEROSTAT.

Specification of Letters Patent.

Patented Nov. 24, 1914.

Application filed March 12, 1913. Serial No. 753,66a.

To all whom it may concern Be it known that I, J onN It. GAMME'rnR,

a citizen of the United States, residing in the city of Akron, county of Summit, and State of Ohio, have invented certain new and useful Improvements in Aerostats, of which the following is a specification.

My invention relates to improvements in aerostats and dirigible balloons, and particularly to the material and structure of the protective envelop inclosing the gas bag or bags in the type of air craft shown and described in my Reissue Patent Number 13,548, dated April 1st, 1913, original Patent Number 1,047,038, dated December 10, 1912.

Among the objects sought by the invention of my prior patent aforesaid was to minimize the risk attendant upon the tendency of the gas in a balloon of impervious elastic material, as rubber, to expand or contract under the influence of atmospheric temperature changes, and means are disclosed therein comprising an exterior envelop woven from ribbons of flexible but substantially inextensible material for relieving the strain upon such contained gas bag or bags, and for maintaining such volume of gas constant therein under varying conditions of atmospheric temperature changes.

My present invention is directed prlmarily to the provision of an improved fabric for such an envelope adapted to protect the contained gas in the inner bag from normal temperature changes, and thus'to assist in the retaining of the volume of gas constant.

secondarily, my invention relates to means for compensating variations in pressure of the contained gas beyond the normal limits of temperature variation, bypermitting changes in volume of the gas,'thus preventing excessive pressure.

These objects of my present lnvention are attainable partly by the use of a partlcular kind of that inextensible fabric which is generically claimed in my said prior patent and partly by the use of the spirally woven construction with which a new principle of operation is attainable, as hereinafter more fully explained.

These several particular features of improvement are realized by the provision of a sheath or envelop for relieving the strain countered and affords a margin.

upon the contained gas bag, which envelop is composed of ribbons woven with a plurality of their warp threads of piano wire or the like, and their woof threads of a material of low heat conductivity, as silk or the like. This novel fabric is particularly adapted for use in spiral weaving in the type of envelop having longitudinal ribbons extending from one end to the other, interwoven with a second series, similarly extending from one end to the other, in that it permits such a structure to attain the function of contraction upon its major axis and circumferential expansion upon increase of pressure of the contained gas, and

reversal of these functions upon the contraction of the contained gas, since it readily allows the mutual play of the woven ribbons and relative movement between the individual warp threads, whereby the envelop provides capacity for an increased volume of gas, should the atmospheric temperature vary for a sufficient period to allow the transmission of heat through the insulating fabric. Such change in contour will only occur when abnormal conditions are enof safety over a structure in which the volume of gas is maintained constant, although with my inextensible fabric presenting no interstices, the range of pressure encountered in practice is well within the limits of safety afforded by the reinforced ribbons, or unitary ribbons.

My invention also provides novel means and methods for the attachment of the ribbons to metallic end caps where employed, and other minor structural features relative to the connection of the individual wire warps to each other and to the means provided of the envelop, and the structure of the partitions therein.

In the accompanying drawings which form a part of this specification, Figure l is a side elevation of a dirigible type of airship, parts being broken away to show the internal construction; Fig. 2 is a bottom view of the same structure; Fig. 3 is a per for affording access to the interior joining the ends of two of these warp wires; Fig. 6 is a fragmentary longitudinal sectional view of a portion of the envelop showing one of the partitions therein in section; Fig. 7 is a fragmentary sectional view on a plane at right angles to the view shown in Fig. (3, showing the partition therein in elevation; Fig. 8 is an enlarged View of a portion of Fig. 7 on a section midway through the partition showing the method of attachment of the warp wires; Fig. 9 is a fragmentary View of an end portion showing the method of attachment of a ribbon thereto; Fig. 10 is a fragmentary view of a portion of one of the ports, showing the i method of attachment of the ribbons thereto: and Fig. 11 is a bottom view of an airship showing the outer envelop spirally woven, and in dotted outline the position assumed by the envelop upon an abnormal increase of the pressure of the contained gas.

Referring to the drawings in detail, the numeral 1 designates a dirigible airship in which the passenger-carrying frame has been removed for the sake of clearness in showing the operating parts. The structure consists of an envelop 2 of closely woven strips or ribbons of flexible but substantially inextensible material. This envelop is riveted or otherwise suitably secured at each end to the cone-like tips 3, 4, which are preferably constructed of-aluminum. This envelop may be divided into sections or compartments 7 by pairs of rings 5 which may preferably be composed of wood. between which are secured partitions 6 of tightly woven material similar to that constituting the envelop. In the drawing I have shown the airship to be divided into three compartments by the use of two partitions, but this arrangement may obviously be altered at will. In Figs. 1 and 2 I have shown the envelop as composed of ribbons extending longitudinally and transversely with respect to the main axis of the structure. In Fig. 11 I have shown the envelop as composed of ribbons spirally interwoven from end to end. The ribbons 8, 8 are composed of the warps 9 of wire and the woof 10 of threads of material of low thermal conductivity. such as silk. The ends of the transverse ribbons are joined as shown in Fig. 2 in a staggered seam, distributing the strain on the envelop, being joined as shown .in Fig. 4 by flattened tubular keepers 11,

each warp wire being passed therethrough and bent down thereover, as shown in Fig. 5. The partitions 6 are comprised of a pair of wooden rings 5, one of which is provided with a series of projecting pins 14 registering with holes in the other member of the pair. One member of this pair is provided with a series of projecting pins 15, to which the warp wires of the transverse and longitudinal bands are attached, as shown in detail in Fig. 8, the woof threads being removed to permit the interweaving of the warp threads. These pins register with holes in the other member of the pair of wooden rings. The method of the attachment of the bands to the terminal cones is illustrated in Fig. 9, the warp wires 9 passing through holes in the caps from inside outwardly and being bent over to hook therein. The port holes 16 provide access to the interior of the envelop and consist of an outer ring 17, preferably of steel, to which the longitudinal and transverse bands are attached by means of the warp wires, engaging the holes therethrough. In Fig. 11 I have shown a portion of the envelop with detail as to the interweaving of strands, but as will be understood, the methods of attachment to the cones and to the port holes is applicable whether the covering is in strands or ribbons.

Theoperation of my improved structure, with particular reference to that embodiment of my invention disclosed in Fig. 11, may be more fully explained with advantage as follows: In my Letters Patent aforesaid I have shown and described an envelop for gas bags for balloons adapted to maintain the volume of contained gas constant under varying conditions of internal pressure resultant from atmospheric changes. As an alternative form of application of my invention, I therein disclosed an envelop woven with spiral ribbons of inextensible material extending from end to end; I now find that with my improved construction of these ribbons with warp threads-of wire and a weft of a material such as silk, I attain the novel results, first, that the contained gas is insulated by the weft threads of the material of low thermal conductivity from sudden temperature changes within certain average limits of change of temperature, and that the rate of expansion of the gas within the envelop is thereby retarded, so that a temporary or transient change of atmospheric temperature such as is customarily encountered inpassing from cloud strata to sunshine, or the reverse, has a more sluggish and less pronounced effect upon the volume of gas; and, second, that by reason of such construction of the ribbons with the ellipsoidal form of envelop, in which ribbonsor bands of wire are interlaced and attached at their extremities to rigid rings, or directly to the cones, the wire ribbons constitute a resilient fabric permitting any abnormal increase of pressure in the gas due to more marked temperature fluctuations, to overcome the countervailing pressure of the containing envelop and both to contract it upon its major axis and to expand it circumferentially without producing appreciable enlargement of the minute interstices between the bands. Thus while the superficial area of the envelop remains substantially constant, its cubical content is increased and an increase in volume of the gas is permitted by the consequent change of contour of the envelop, and the pressure is correspondingly prevented from rising to a dangerous point. Ordinarily the insulating medlum suffices to maintain a.

constant temperature in the gas, but with the application of these means in conjunction with the spiral weaving of the envelop, abnormal increases in temperature are also compensated for, by reason of constructing the envelop of spirally interlaced ribbons the change in contour of the envelop is attainable. Hence it is of especial advantage to employ the wire bands with the spiral weaving where abnormal variations of pressure are liable to be encountered, and particularly where the gas bags are to be charged for an unusually prolonged flight and the initial pressure is therefore at its maximum. Due to the resilience of the envelop, changes in volume of the contained gas are compensated correspondingly by change in contour of the envelop, which resumes its initial shape when the abnormal pressure is reduced, owing tothe inherent resilience of its structure. Thus with the construction shown in Fig. 11 variations in temperature of the gas within the envelop are minimized within normal limits, and beyond these limits variations are compensated by changes in contour of the envelop, tending to maintain the gas at relatively constant pressure. These results secure greater stability in the aerostat by its automatic adjustment to the varying external temperature conditions.

\Vhile I prefer a flexible but nondeformable envelop to take the strain from its inclosed gas bag and to maintain the volume of contained gas ,constant under usual conditions, and in ,the illustrated embodiment of my invention have shown it as applied to such preferred form in Figs. 1 and 2,- yet, as stated, under conditions of extreme temperature changes or maximum pressure of inflation, the alternative form illustrated in Fig. 11, in which the wires or bands of wire are spirally interlaced'and attached to rigid end portions, has these positive features ofadvantage resultant from maintaining the pressure more nearly constant. These result from the adaptability of'this form of construction to contraction upon its major axis, and expansion circumferentially, upon an increase in pressure of the contained gas, since increased cubical capacity is thereby afforded without loss of any .of the benefits obtainable from the use of inextensible fabric and such extension of my improvement supplements the factor of safety provided by it. Although resiliency of the envelop is attainable by the form of construction of the spiral weaving, yet the adaptability of the structure to yield in compensation for an increase in pressure and so maintain it more nearly constant, and to contract upon decrease in pressure, is materially facilitated by the accommodation of the individual wires to relative strains. By permitting play relatively to each other and between the bands into which the wires are woven as groups, greater flexibility results in the mutual accommodation of the units without substantially enlarging the minute interstices between the warp and weft bands, and the envelop alters its contour and consequently its cubical capacity, without that degree of frictional resistance encountered with metallic or similar ribbons of unitary .construction. As the ribbons are necessarily thin, destructive wear from relative motion is to be avoided so far as possible, but with the wire ribbons of my present fabric, the expansion and contraction of the spirally woven envelop entails a minimum of frictional resistance While I have thus described'my invention and explained the principle thereof and the best mode known to me of its application, I believe that it is susceptible of extensive application in various equivalent forms, and that such principle, without departing from the spirit thereof, may be embodied in many varieties ofstructure, as, for example, it is within the scope of my invention to employ an envelop composed of a fabric whose warp and woof threads are individual wires suitably insulated thermally, and I therefore desire to cover my improvement in claims commensurate therewith without limitation, save as expressly made in certain of the more specific claims.

Having thus described my invention, I claim:

1. An envelop for gas bags for aerostats composed of strain members of a material of high tensile strength and insulating members of a material of low thermal conductivity, the individual strain members being spaced from each other and from the external atmosphere by said insulating members.

2. An envelop for gas bags for balloons comprising an outer ply of low thermal conductivity and an inner ply of ,dnextensible vmaterial said plies being interwoven.

3. An envelop for gas bags for balloons composed of interwoven ribbons -whose warps are of wire.

4. An envelop for gas bags for balloons composed of interwoven ribbons whose warps are of wire and whose woof is of a material of low thermal conductivity.

5. An envelop for-gas bags for balloons composed of interwoven wires, said wires being individually covered with heat insulating material.

6. Anenvelop for gas bags for balloons composed of interwoven ribbons having a plurality of warp threads of wire.

7. An envelop for gas containers for aerostats consisting of a web whose Warp and woof are ribbons having their warps of wire.

8. An envelop for gas containers for aerostats consisting of a web whose Warp consists of ribbons having their warps of wires.

9. An envelop for gas containers for aerostats composed of interwoven ribbons whose warp consists of a plurality of wires in a single layer and whose woof consists of a material of low thermal conductivity.

10. An envelop for gas containers for aerostats composed of interwoven ribbons whose warp consists of a plurality of parallel wires and whose woof consists of a nonconductor of: at.

11. A fabric for gas bags for balloons' consisting of a web of ribbons whose warps are wires and whose woof is silk.

12. A fabric for gas bags for balloons consisting of a web of inextensible ribbons, a plurality of the warps of each ribbon consisting of wires and an exterior ply of mate-.

rial of low thermal conductivity.

13. A fabric for gas bags for balloons 16. A resilient envelop for elastic bags for gas composed of bands of wire spirally interlaced and attached to rigid end portions and adapted to be contracted upon its major axis and expanded circumferentially by an increase of pressure of the contained gas and to resume its normal contour upon such pressure being reduced.

17. An envelop for gas bags comprising an ellipsoidal sheath presenting a substantially constant superficial area and capable of simultaneous changes of its major and minor axes to provide a variable cubical capacity.

18. An envelop for aerostats comprising end portions and a body portion formed of a seriesof flexible ribbons extending spirally fromvend to end, and a second series of spirally arranged ribbons angularly disposed with reference to the first and interwoven therewith, said envelop having a substantially constant superficial area but being capable of a change in contour to provide a "ariable cubical capacity.

19. An envelop for aerostats comprising a series of interengaging flexible ribbons extending longitudinally thereof and forming a sheath substantially ellipsoidal in shape, capable of simultaneous expansion along its minor axis and contraction on its major axis in response to an increase in internal pressure. i

20. An envelop for aerostats comprising a series of interengaging flexible ribbons extending longitudinally'thereof and forming a sheath substantially ellipsoidal in shape,

capable of a limited change in the ratio of its major. and minor axes in response to variations in the ratio of internal and exter- JOHN R. GAMMETER. Witnesses:

WALTER K. MEANS, ILLA N. KIRN. 

